1. Field of the Invention
The present invention relates to an information processing apparatus (e.g., printer), a control method for the information processing apparatus, a display apparatus (e.g., digital TV broadcasting receiver), and a control method for display apparatus, for previewing print data generated from printing structured document data described in a markup language, before printout of the print data.
2. Description of the Related Art
There have been known information processing apparatus which generate print data based on printing structured document data described in a markup language. A well-known example of such an information processing apparatus is a printing apparatus configured to handle digital TV broadcasting (hereafter referred to simply as “printer”).
Japanese digital TV broadcasting includes so-called data broadcasting. The ARIB (Association of Radio Industries and Businesses) has stipulated that printing services should be able to be provided using this data broadcasting framework (hereafter referred to as data broadcasting printing).
Two general types of data broadcasting printing exist. The first method involves a digital TV broadcasting receiver receiving the actual printing contents included in data broadcasting data multiplexed with the broadcast waves, and transferring the printing contents to a printer. The printer uses the actual printing contents received and generates print data. Hereinafter, this method will be referred to as the “print file method”.
The second method involves a digital TV broadcasting receiver receiving address information indicating where the printing contents are stored, and transferring the address information to the printer. The printer which has received the address information obtains the actual printing contents based on the address information, and generates printing data. Hereinafter, this method will be referred to as the “print URI method”.
Standards for Japanese data broadcasting stipulate using a page description language (markup language) for data broadcasting called BML (Broadcast Markup Language). BML has been formulated based on XML (extensible Markup Language). The ARIB stipulates that data broadcasting printing is to conform to XHTML (extensible HyperText Markup Language)-Print and CSS (Cascading Style Sheets) Print Profile. XHTML-Print stipulates elements and attributes of print data. Also, CSS Print Profile (hereafter abbreviated to “CSSPP”) stipulates the layout, font size, and so forth of print data. That is to say, the printing contents data includes printing structured document data such as XHTML files and CSS files. Also, depending on the contents, MonoMedia data such as JPEG files or PNG files regarding which a path is described in the XHTML file is included. Hereinafter, description will be made with the understanding that printing contents data includes at least printing structured document data.
With both the above described print file method and print URI method, the printer generates the final print data. This is also as stipulated. That is to say, the printer parses XHTML files and CSS files, and performs rendering to generate bitmap data. Accordingly, digital TV broadcasting receivers such as digital TV sets basically are not provided with functions to parse printing contents and generate image data. Accordingly, in the event that the user desires to display an outline of the print data on the screen of the digital TV as a preview, a conceivable arrangement would be for the printer to generate printing image data, and transmit the printing image data to the digital TV. This method has been disclosed in Japanese Patent Laid-Open No. 2000-112691.
BML browser applications and HTML browser applications (hereafter referred to simply as “browser”) implemented in current digital TV broadcasting receivers are capable of displaying BML contents in normal data broadcasting and HTML contents ordinarily on the Internet, respectively. However, it has been difficult for such browsers to display printing structured document data encoded with XHTML-Print or CSSPP.
One reason is that parsing and rendering XHTML files for previewing requires a great amount of memory and CPU power. While digital TV broadcasting receivers do have memory and CPUs, previewing would require additional memory capacity and CPU power, increasing of which may not be feasible.
A second reason is that even if one attempted to display printing structured document data encoded with XHTML-Print or CSSPP using a BML browser or HTML browser, these browsers cannot suitably parse elements and attributes dependent on printing processing. Consequently, the display would be of a different layout and display from the actual print data, meaning that the preview does not work.
Further, with the method disclosed in Japanese Patent Laid-Open No. 2000-112691, even in cases of just performing a preview, the printer has to first generate the print data, and then generate image data such as a BMP image or JPEG image. This leads to an increase in both processing time and processing load, and further, the printer needs an encoder and memory for generating data.